My goal is to elucidate the role of the Androgen Receptor Trapped clone-27 (ART-27) in androgen mediated prostate cell growth and differentiation. ART-27 is a newly described transcriptional co-activator of the androgen receptor (AR) and may play a role as a tumor suppressor gene in the prostate. I hypothesize that ART-27 facilitates androgen-dependent differentiation of prostate epithelial cells by helping AR regulate a subset of genes important to prostate growth suppression and differentiation. I further hypothesize that alterations in the level of ART-27 modulates AR activity, which, in turn, affect AR-dependent cell growth regulation in vivo. To test these hypotheses, I will 1) analyze AR-dependent gene expression as a function of ART-27 in prostate cancer cells using DNA microarrays; 2) assess the effect(s) of ART-27 overexpression in prostatic epithelia in vivo using a transgenic mouse model; 3) Identify factors that interact with ART-27 using the yeast two hybrid system.